1. Technical Field
The present invention relates to an adhesion-preventing material and a process for preventing adhesion, in particular to an adhesion-preventing material which is capable of effectively preventing the surfaces of organs from adhesion, and which can be absorbed in the body with high safety and manufactured with ease and has high practical utility, as well as to a process for preventing adhesion by using the adhesion-preventing material.
2. Background Art
Organs are generally in a state which can be freely moved or separated with each other even if the surface of an organ is in proximal contact with that of the other organ. However, adhesion between organs may be caused by inflammation due to operation or some other causes, which brings about deuteropathy such as hypofunctions of local organs. When the adhesion of organs is caused, it is necessary to conduct re-operation, which increases the burden on the patient, and the operation is very difficult to be completed.
Adhesion-preventing materials have been proposed for the purpose of preventing the adhesion of organs.
Adhesion-preventing materials are broadly classified into non-absorbent and absorbent materials.
The non-absorbent materials include silicone sheet, GoreTex sheet, organ-adhesion preventing films comprising a hydrogel film of a mixed polymer which comprises polyvinyl alcohol and a prescribed water-soluble polymer (see Patent Reference 1). While these sheets physically isolate a damaged site by affixing the sheet to the site, resulting in no adhesion, they are not absorbed in the body and thus offer a problem that an artificial material remains in the body.
Furthermore, the non-absorbent sheet or film thus affixed itself may cause dysfunction by adhering to organs. In this case, it will be impossible to remove the sheet thus adhered to the organs even by re-operation.
Therefore, it has been attempted to develop absorbent base materials which can be absorbed in the body with high safety.
There have been proposed, as the absorbent base material, gelatin, fibrin glue, hyaluronic acid and salts thereof, cellulose, as well as an adhesion-preventing material comprising poly-γ-glutamate complexes formed by hydrogen bonding of the carboxy anion of the poly-γ-glutamate with chitosan or the like (see Patent Reference 2), a radiation-sterilizable medical material comprising a bioavailable polymer and a multi-functional triazine compound such as triallyl-isocyanurate contained therein(see Patent Reference 3), and the like.
While the absorbent base materials can be repeatedly used in the same site with high safety, only a few of the materials have been recognized effective in animal experiments and thus it is difficult to say that the materials have been spread clinically. Especially, high probability of side effects may be found in such materials comprising animal proteins as the primary ingredient, and a two-ingredient based material such as the adhesion-preventing materials disclosed in Patent References 2 and 3.
Moreover, a biodegradable and highly water-absorbent material composed of a radiation-crosslinked poly-γ-glutamate polymer having a gelation degree of 40-90% has been proposed in Patent Reference 4. Patent Reference 4 focuses on the manufacturing conditions, water absorption properties and biodegradability of the biodegradable and highly water-absorbent material. However, Patent Reference 4 does not disclose the use of the highly water-absorbent material as an adhesion-preventing material.
Patent Reference 1: Japanese Patent No. 2840729,
Patent Reference 2: Japanese Patent Laid-Open Publication No. 276572/1999,
Patent Reference 3: Japanese Patent Laid-Open Publication No. 695/2003,
Patent Reference 4: Japanese Examined Patent Publication No. 72267/1995.